API JavaMail - Buscando e-mails
No capítulo anterior, aprendemos como verificar e-mails. Agora vamos ver como obter cada e-mail e ler seu conteúdo. Vamos escrever uma classe JavaFetchingEmail que lerá os seguintes tipos de e-mails:
Email simples
Email com anexo
Email com imagem embutida
As etapas básicas seguidas no código são as seguintes:
Obtenha o objeto Session.
Crie um objeto de armazenamento POP3 e conecte-se ao armazenamento.
Crie o objeto Pasta e abra a pasta apropriada em sua caixa de correio.
Recupere mensagens.
Feche a pasta e armazene os objetos respectivamente.
Criar classe Java
Crie um arquivo de classe java FetchingEmail, cujo conteúdo é o seguinte:
package com.tutorialspoint;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Date;
import java.util.Properties;
import javax.mail.Address;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.NoSuchProviderException;
import javax.mail.Part;
import javax.mail.Session;
import javax.mail.Store;
public class FetchingEmail {
public static void fetch(String pop3Host, String storeType, String user,
String password) {
try {
// create properties field
Properties properties = new Properties();
properties.put("mail.store.protocol", "pop3");
properties.put("mail.pop3.host", pop3Host);
properties.put("mail.pop3.port", "995");
properties.put("mail.pop3.starttls.enable", "true");
Session emailSession = Session.getDefaultInstance(properties);
// emailSession.setDebug(true);
// create the POP3 store object and connect with the pop server
Store store = emailSession.getStore("pop3s");
store.connect(pop3Host, user, password);
// create the folder object and open it
Folder emailFolder = store.getFolder("INBOX");
emailFolder.open(Folder.READ_ONLY);
BufferedReader reader = new BufferedReader(new InputStreamReader(
System.in));
// retrieve the messages from the folder in an array and print it
Message[] messages = emailFolder.getMessages();
System.out.println("messages.length---" + messages.length);
for (int i = 0; i < messages.length; i++) {
Message message = messages[i];
System.out.println("---------------------------------");
writePart(message);
String line = reader.readLine();
if ("YES".equals(line)) {
message.writeTo(System.out);
} else if ("QUIT".equals(line)) {
break;
}
}
// close the store and folder objects
emailFolder.close(false);
store.close();
} catch (NoSuchProviderException e) {
e.printStackTrace();
} catch (MessagingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
String host = "pop.gmail.com";// change accordingly
String mailStoreType = "pop3";
String username =
"[email protected]";// change accordingly
String password = "*****";// change accordingly
//Call method fetch
fetch(host, mailStoreType, username, password);
}
/*
* This method checks for content-type
* based on which, it processes and
* fetches the content of the message
*/
public static void writePart(Part p) throws Exception {
if (p instanceof Message)
//Call methos writeEnvelope
writeEnvelope((Message) p);
System.out.println("----------------------------");
System.out.println("CONTENT-TYPE: " + p.getContentType());
//check if the content is plain text
if (p.isMimeType("text/plain")) {
System.out.println("This is plain text");
System.out.println("---------------------------");
System.out.println((String) p.getContent());
}
//check if the content has attachment
else if (p.isMimeType("multipart/*")) {
System.out.println("This is a Multipart");
System.out.println("---------------------------");
Multipart mp = (Multipart) p.getContent();
int count = mp.getCount();
for (int i = 0; i < count; i++)
writePart(mp.getBodyPart(i));
}
//check if the content is a nested message
else if (p.isMimeType("message/rfc822")) {
System.out.println("This is a Nested Message");
System.out.println("---------------------------");
writePart((Part) p.getContent());
}
//check if the content is an inline image
else if (p.isMimeType("image/jpeg")) {
System.out.println("--------> image/jpeg");
Object o = p.getContent();
InputStream x = (InputStream) o;
// Construct the required byte array
System.out.println("x.length = " + x.available());
while ((i = (int) ((InputStream) x).available()) > 0) {
int result = (int) (((InputStream) x).read(bArray));
if (result == -1)
int i = 0;
byte[] bArray = new byte[x.available()];
break;
}
FileOutputStream f2 = new FileOutputStream("/tmp/image.jpg");
f2.write(bArray);
}
else if (p.getContentType().contains("image/")) {
System.out.println("content type" + p.getContentType());
File f = new File("image" + new Date().getTime() + ".jpg");
DataOutputStream output = new DataOutputStream(
new BufferedOutputStream(new FileOutputStream(f)));
com.sun.mail.util.BASE64DecoderStream test =
(com.sun.mail.util.BASE64DecoderStream) p
.getContent();
byte[] buffer = new byte[1024];
int bytesRead;
while ((bytesRead = test.read(buffer)) != -1) {
output.write(buffer, 0, bytesRead);
}
}
else {
Object o = p.getContent();
if (o instanceof String) {
System.out.println("This is a string");
System.out.println("---------------------------");
System.out.println((String) o);
}
else if (o instanceof InputStream) {
System.out.println("This is just an input stream");
System.out.println("---------------------------");
InputStream is = (InputStream) o;
is = (InputStream) o;
int c;
while ((c = is.read()) != -1)
System.out.write(c);
}
else {
System.out.println("This is an unknown type");
System.out.println("---------------------------");
System.out.println(o.toString());
}
}
}
/*
* This method would print FROM,TO and SUBJECT of the message
*/
public static void writeEnvelope(Message m) throws Exception {
System.out.println("This is the message envelope");
System.out.println("---------------------------");
Address[] a;
// FROM
if ((a = m.getFrom()) != null) {
for (int j = 0; j < a.length; j++)
System.out.println("FROM: " + a[j].toString());
}
// TO
if ((a = m.getRecipients(Message.RecipientType.TO)) != null) {
for (int j = 0; j < a.length; j++)
System.out.println("TO: " + a[j].toString());
}
// SUBJECT
if (m.getSubject() != null)
System.out.println("SUBJECT: " + m.getSubject());
}
}Você pode ativar a depuração removendo o comentário da instrução emailSession.setDebug (true);
Compilar e executar
Agora que nossa classe está pronta, vamos compilar a classe acima. Salvei a classe FetchingEmail.java no diretório:/home/manisha/JavaMailAPIExercise. Precisamos dos jars javax.mail.jar e activation.jar no classpath. Execute o comando abaixo para compilar a classe (ambos os jars são colocados no diretório / home / manisha /) no prompt de comando:
javac -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: FetchingEmail.javaAgora que a classe está compilada, execute o comando abaixo para executar:
java -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: FetchingEmailVerificar saída
Você deve ver a seguinte mensagem no console de comando:
messages.length---3
---------------------------------
This is the message envelope
---------------------------
FROM: XYZ <[email protected]>
TO: ABC <[email protected]>
SUBJECT: Simple Message
----------------------------
CONTENT-TYPE: multipart/alternative; boundary=047d7b343d6ad3e4ea04e8ec6579
This is a Multipart
---------------------------
----------------------------
CONTENT-TYPE: text/plain; charset=ISO-8859-1
This is plain text
---------------------------
Hi am a simple message string....
--
Regards
xyz
This is the message envelope
---------------------------
FROM: XYZ <[email protected]>
TO: ABC <[email protected]>
SUBJECT: Attachement
----------------------------
CONTENT-TYPE: multipart/mixed; boundary=047d7b343d6a99180904e8ec6751
This is a Multipart
---------------------------
----------------------------
CONTENT-TYPE: text/plain; charset=ISO-8859-1
This is plain text
---------------------------
Hi I've an attachment.Please check
--
Regards
XYZ
----------------------------
CONTENT-TYPE: application/octet-stream; name=sample_attachement
This is just an input stream
---------------------------
Submit your Tutorials, White Papers and Articles into our Tutorials Directory. This is a tutorials database where we are keeping all the tutorials shared by the internet community for the benefit of others.
This is the message envelope
---------------------------
FROM: XYZ <[email protected]>
TO: ABC <[email protected]>
SUBJECT: Inline Image
----------------------------
CONTENT-TYPE: multipart/related; boundary=f46d04182582be803504e8ece94b
This is a Multipart
---------------------------
----------------------------
CONTENT-TYPE: text/plain; charset=ISO-8859-1
This is plain text
---------------------------
Hi I've an inline image
[image: Inline image 3]
--
Regards
XYZ
----------------------------
CONTENT-TYPE: image/png; name="javamail-mini-logo.png"
content typeimage/png; name="javamail-mini-logo.png"Aqui você pode ver que há três emails em nossa caixa de correio. Primeiro, um e-mail simples com a mensagem "Olá, sou uma string de mensagem simples ....". O segundo e-mail contém um anexo. O conteúdo do anexo também é impresso conforme visto acima. O terceiro e-mail tem uma imagem embutida.